1. Field of the Invention
The present invention relates to tape cartridges, and more particularly to tape cartridges which can be mounted in and removed from a printing apparatus having a printing head, printing tape and a platen for nipping the printing tape in cooperation with the printing head in such a manner that printing can be produced thereon when the tape cartridge is mounted on the printing apparatus.
2. Description of the Related Art
Devices for printing a desired string of characters on the front surface of an adhesive tape with an adhesive coating on the rear surface thereof have been previously known. Such a printing apparatus enables the user to readily print, for example, a headline or a title on the surface of a tape, with the printed tape being easily adhered to the spine or cover of a document file or to the spine of a video tape. Such a printing apparatus is very useful and is extensively used in industrial fields and households.
Various attempts have been made to realize the desired goals of reduced size and weight in such printers. One method for achieving these objectives is an improvement in a printing section of the printing apparatus which typically requires a large space for installation. MA printing apparatus has therefore been proposed, with the apparatus having a structure in which a platen for enabling printing on a tape in cooperation with a printing head is provided in a tape cartridge. During printing, the printing head nips a printing tape in cooperation with the platen. The above-described structure enables the tape cartridge to be readily replaced by retracting the printing head and replacing the cartridge.
Printing tapes typically differ in material, width and color and different types of ink ribbons may be used to print on the tapes. Tape cartridges which can accommodate various types of printing tapes are commercially available. For a given application, the user selects a tape cartridge which can accommodate the type of tape suited to the application from among various types of tape cartridges, and mounts it on the printing apparatus.
However, the ability of such tape cartridges to accommodate different types of tapes may lead to a significant decline in print quality depending on the particular combination of printing apparatus and type of printing tape. Specifically, a desired contact state between the printing head and the tape cannot be obtained when a tape cartridge which accommodates, for example, a thick tape is mounted in a printing apparatus originally designed to employ a thin tape or conversely when a tape cartridge which accommodates a thin tape is mounted in a printing apparatus originally designed to employ a thick tape. If the desired contact state between the printing head and the tape is not achieved, the print quality is adversely affected. One solution to the problem of poor contact between the printing head and the tape is to provide in the printing apparatus a mechanism for adjusting the position of the printing head in accordance with the thickness of the tape. However, the use of this method makes the entire structure of the apparatus more complicated. A further problem with this method is that for a given tape cartridge, the user must check whether the adjusting mechanism of the printing apparatus is in a state corresponding to the thickness of the tape accommodated in the mounted tape cartridge. If the mechanism is not set to accommodate the appropriate tape thickness, the user must operate the adjusting mechanism, making the use of such a printing apparatus troublesome. The above-described problems occur not only with respect to the thickness of the tape accommodated in the tape cartridge but also with respect to the width and hardness of the tape as well as the width of the ink ribbon.
Certain combinations of platens and ink ribbons may also lead to ink smears on the printing tape. When the tape cartridge is mounted in the printing apparatus, the tape and the ink ribbon are pressed against the platen by the printing head. If the width of the tape and ink ribbon is larger than the width of the printing head and if the platen is made of a relatively soft material, the pressure of the printing head will significantly deform the platen, and the tape and ink ribbon will be firmly pressed against the edges and end portions of the printing head. In such a situation, the ink may be undesirably transferred to the printing tape.